Status of qnr and aac(6’)-lb-cr Genes in Quinolone-Resistant Non-Fermenters

Non-fermenters are aerobic non-spore forming Gram-negative bacilli that either incapable of catabolized carbohydrates as a source of energy or degrade them via oxidative rather than fermentative metabolic pathways. In the group of non-fermenters Pseudomonas aeruginosa is eminent pathogen followed by Acinetobacter baumanni. Both of these organisms are reported for their intrinsic resistance against antibiotics and their ability to acquire gens that encode resistance. Resistant against quinolones like ciprofloxacin is common against Gram’s negative non-fermenters. For most of the mechanism of resistant in both of these organisms against quinolone, is the production of aminoglycoside modifying enzymes, mutations in topoisomerases, up-regulation of efflux pumps and presence of plasmid mediated qnr genes. In this study, during the study period total 94 non-fermenters were isolated from 378 numbers of different clinical specimens. Out of 94; 21 isolates were found resistant against quinolone antibiotics like ciprofloxacin-5 μg, levofloxacin-5 μg , norfloxacin-10 μg, which were subjected for PCR studies to detect resistant genes, only five (23.81%) isolates were found to be associated with aac(6’)-lb-cr and two (9.52%) were found positive for carrying qnrD gense as additional with aac(6’)-lb-cr genes. Organisms that processed qnrD and aac(6’)-lb-cr gens were, Pseudomona aeruginosa, Acinetobacter baumanni , Alcaligenes faecalis , Acinetobacter calcoaceticus, and Pseudomonas sp. Key word: Non-fermenters, Quinolone resistant, PCR studies, QNR, aac(6’)-Ib-cr.